Merge lp:~hloeung/ubuntu-repository-cache/health-check-flush-output-buffers into lp:ubuntu-repository-cache

[Haw Loeung]

Avoid holding up connection/request based on sending metrics and flush buffers - LP:1917317

[David Lawson (deej)]

LGTM

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 323

=== modified file 'files/health_check.py'
--- files/health_check.py	2021-03-03 22:57:07 +0000
+++ files/health_check.py	2021-03-03 23:03:25 +0000
@@ -75,7 +75,7 @@
         print('Status: 503 Service Unavailable')
         print('Content-type: text/html\n')
         disabled_time = os.stat(disabled_flag).st_mtime
-        print('Currently disabled for maintenance since {}'.format(time.ctime(int(disabled_time))))
+        print('Currently disabled for maintenance since {}'.format(time.ctime(int(disabled_time))), flush=True)
         logging.info('DISABLED since {:.3f}'.format(disabled_time))
         # Rather than 0 here, we want to make maintenance/disabled
         # units stand out a little in the grafana graphs, so 5.03s with
@@ -89,7 +89,7 @@
     if not os.path.exists(os.path.join(apache_root, 'data', 'ubuntu_active')):
         print('Status: 503 Service Unavailable')
         print('Content-type: text/html\n')
-        print('Currently provisioning or missing metadata')
+        print('Currently provisioning or missing metadata', flush=True)
         logging.warning('DISABLED ubuntu_active missing')
         # Rather than 0 here, we want to make disabled units stand out
         # a little in the grafana graphs, so 4.04s with the average
@@ -154,6 +154,10 @@
         labels = 'url={},status=SUCCESS,status_code={}'.format(url, status_code)
         metrics.append(render_influx(METRIC_NAME, labels, duration))
 
+    # Flush the buffer to ensure we're not holding up
+    # request/connection on sending metrics to influx.
+    print('', flush=True)
+
     for metric in metrics:
         send_to_influx(metric)